SCOTTSDALE, Ariz. -- One pitcher will be in the Giants’ season-opening starting rotation; another hopes to be there. Both were on the mound Sunday afternoon at Scottsdale Stadium.

Logan Webb was so raring to go that he changed his initial Sunday plan to throw a bullpen session to instead get the starting call in the Cactus League game against the Rockies, who wound up with a 5-3 victory.

Keaton Winn, meanwhile, made his 2024 Spring Training debut in the eighth inning to put his healing right elbow to the test. He’s hoping to snare that fifth and final rotation spot by the time Opening Day rolls around March 28 in San Diego.

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“I felt good in the bullpen; I just wanted to get out and compete in a real game,” Webb said of his Sunday switch.

The stat line didn’t look pretty. Webb was tagged for four runs on six hits in his 5 1/3 innings, but he struck out eight with no walks.

“I felt more like myself today,” Webb said.

Webb’s changeup and slider were strong. And defensively he made a sweet grab on a hot, one-hop comebacker to the mound in the second inning.

Webb points to poor pitch selection for why he struggled to get out of a couple jams. In the fifth, the Rockies put runners at second and third. Webb had two strikes on the next two batters, but the Rockies were able to put three runs across in the frame.

As for Winn, manager Bob Melvin said that the 26-year-old righty has a chance to compete for the fifth rotation spot despite elbow soreness that kept his spring pace behind other rotation candidates. The Giants’ No. 13 prospect in the MLB Pipeline rankings, Winn threw 26 pitches, 16 for strikes, and then threw a simulated inning in the bullpen after the game.

“It felt good to actually get some adrenaline on the mound,” Winn said. “The four-seam and the sinker, they both felt good. I still need to get some higher intensity reps for the split.”

Winn preached patience for himself despite his late start to spring competition. Not only does his arm “feel really good,” he knows he’s still in the running for the rotation.

“It’s really encouraging,” he said. “It seems like they really want me to take that spot.”

Without locking in the order, Melvin on Sunday confirmed a rotation of Webb, lefty Kyle Harrison and righty Jordan Hicks, along with No. 8 prospect Mason Black, a righty who will pitch a Minor League game at Papago Park on Tuesday.

“Day 5 still is in play, but we’ll see how we get there,” Melvin said.

Other No. 5 candidates
Righty Alex Cobb struck out five and allowed no hits or walks over two innings in his 27-pitch Minor League outing Saturday. But he continues to recover from offseason surgery on his left hip, and Melvin said on Sunday that he doesn’t expect Cobb to be ready for Opening Day. Look for Cobb’s return around May 1, at the earliest, though he should get into one more spring game in Arizona.

That leaves Winn and non-roster righties Spencer Howard and Daulton Jeffries as the candidates.

Jeffries threw four scoreless innings Saturday with a walk and three strikeouts against the Guardians and has added a slider as a true third pitch. He appeared in a handful of games with the A’s in 2020 and 2021 during Melvin’s tenure as Oakland manager.

This spring, batters are hitting .176 off Howard. He has a 1.86 ERA in four starts.